Tip on jittery or twitchy screen displays

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tmtomh's picture
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I remember a recent post (during the final days of AFF 1.0 IIRC) in which someone did a VGA mod and said it was basically okay but the display was a bit twitchy.

I recently did my first VGA mod ( Laughing out loud ), and the display was fine. But then I had to disassemble the unit for something, and when I reassembled it, lo and behold the screen image was jittery.

Did some looking, and I realized that the orange connector on a wire that goes from the video board to the metal cage on the analog board was loose, almost disconnected. I'm referring to the connector that's about 1/3 from the top and 1/3 from the right in the following photo:

http://www.colourclassicfaq.com/highres/img/mac640_7.jpg

It's the connector just above the leftmost adjutment pot hole on the analog board.

Anyway, I reattached the connector, and the screen jitteriness went away.

I wanted to confirm that this connector was the cause when I had the unit on, but I was too chicken to wriggle it around with the unit powered up. Embarrassed

Is this connector for some kind of grounding? Anyone know its function?

Matt

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tmtomh's picture
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Joined: Dec 20 2003
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Correction on URL

!@#$% new URL link tool!

This should work:

http://www.colourclassicfaq.com/highres/img/mac640_7.jpg

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That connector is to the de-g

That connector is to the de-gauss cables around the CRT. Stuart

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My suspicion is that although

My suspicion is that although he is *holding* the de-gauss connector, what he is actually referring to is the ground wire connector from the PCB.

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tmtomh's picture
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Sorry for the confusion, guys

Sorry for the confusion, guys -- I was in a rush so I just grabbed a pic from the High-Res modification procedure in the CC FAQ. The guy in the pic -- that's not me! -- is in fact holding the degauss cable, but dead_elvis is correct: I am referring to the ground wire connector from the PCB.

Matt